The present invention relates generally to a sprinkler system, and more particularly to a sprinkler system construction and to a method of operating the same.
Various types of sprinkler systems are already well known in the art. One type which is of particular interest in the context of the present invention involves a sprinkler conduit (which may be composed of a plurality of conduit sections) which is filled with gas under pressure and separated from a water supply conduit by a valve which is normally closed. Such systems are well known and may include a so-called "pre-action" system. In the type of sprinkler system which uses only a pressurized sprinkler conduit, the valve connecting the sprinkler conduit with the water supply conduit opens when it senses a pressure drop in the sprinkler conduit, for instance because pressurized gas can escape from the same due to the fact that one or more of the sprinklers of the sprinkler conduit have opened, if, however, the system is of the type using a "pre-action" system, then the valve connecting the sprinkler conduit with the water supply conduit is not opened when a pressure drop occurs in the sprinkler conduit itself, but instead is opened only in response to the operation of a separate fire alarm system. In this case, the opening of one or more sprinklers of the sprinkler conduit will result only in the giving of a signal indicative of the fact that the pressure in the sprinkler conduit has dropped. The operation of the fire alarm system also produces a signal, and at the same time opens the valve which separates the sprinkler conduit from the water supply conduit. However, only if two conditions are met can the sprinkler system operate in these circumstances, namely one or more sprinklers must be open and the fire alarm system must detect a fire and open the valve separating the sprinkler conduit from the water supply conduit.
This type of combined system is used only for certain purposes, for the simple reason that the additional pre-action system with its fire alarm imposes a check upon the operation of the sprinkler system which does not exist in prior-art sprinkler systems that do not have a pre-action system. Of course, this combined type of system has its advantages, namely if it is for instance installed in structures housing computer installations or the like, where it is absolutely essential that water damage be incurred only if a fire is actually present, not if for some reason one of the sprinklers of the system should malfunction and open without the presence of a fire. The disadvantage of this type of system is, of course, the fact that if the fire alarm system should not properly operate, either as an actual malfunction or because the electrical energy required for its operation should not be available, the sprinkler system cannot operate at all, even if one or more of the sprinklers themselves should open. This means, in other words, that a fire might conceivably occur which would not be put out by operation of the sprinkler system, because the latter would be prevented from operating (even though its sprinklers should open) by the fact that the valve separating it from the water supply conduit is maintained closed due to the failure of the pre-action system to operate.